Prion protein hereditary amyloidosis: Parenchymal and vascular

Prion protein (PrP) amyloidosis is a feature of Gerstmann-Straussler-Scheinker disease (GSS) and prion protein cerebral amyloid angiopathy (PrP-CAA). GSS and PrP-CAA are associated with point mutations of the prion protein gene (PRNP); there is a broad spectrum of clinical presentations and the main signs are ataxia, spastic paraparesis, extrapyramidal signs and dementia. In GSS, parenchymal amyloid may be associated with spongiform changes or neurofibrillary lesions; in PrP-CAA, vascular amyloid is associated with neurofibrillary lesions. In the two diseases, a major component of the amyloid fibrils is a 7 kDa peptide, approximately spanning residues 81-150 of PrP.